Transducers of the type adapted to be inserted in such a bore are suggested in the prior art. For example, U.K. Pat. No. 2,050,624 shows a cylindrical plug provided with a transversely extending diaphragm wall on one end of the plug. Strain gages are provided on the wall, and an enclosure is provided for the circuitry required to monitor incremental changes in the resistivity of the strain gages.
U.S. Pat. No. 4,530,245 also shows a transducer adapted to be inserted in a hole or bore within a structural member, and in this prior art apparatus the strain gages are also provided in a protective enclosure albeit the signals from the strain gages are carried outside of the immediate vicinity of the transducer to be incorporated in a conventional bridge circuit.